The trader allegedly responsible for the 2010 Flash Crash has been taken into custody in the U.K., the Justice Department announced. Photo: Reuters

The U.S. Justice Department has unsealed charges against a futures trader for stock market manipulations that allegedly caused the 2010 “Flash Crash,” a historic market swing that brought national attention to high-frequency trading.

Navinder Singh Sarao, 37, was arrested in the U.K., where American authorities have requested extradition. The DOJ plans to bring 22 charges against Sarao, including counts of commodities fraud and wire fraud.

Sarao allegedly used an algorithmic trading program to manipulate the market for S&P 500 futures contracts sold on the Chicago Mercantile Exchange. The securities, called E-Minis, have long been fingered as the central culprits in the Flash Crash.

According to the Justice Department complaint, Sarao employed a technique called layering, in which a trader posts multiple sell orders at different prices, only to cancel the majority of them. The appearance of increased supply artificially depresses prices and allows a high-frequency trader to buy and sell on the price fluctuations that result.

But around 2:40 p.m. on May 6, 2010, the scheme went awry. The Dow Jones Industrial Average plunged more than 600 points in mere minutes before rebounding and stabilizing. According to a Securities and Exchange Commission report filed months later, nearly 140,000 E-Mini sell orders flooded the market in the moments leading up to the crash.

The charges revealed Tuesday by the Commodity Futures Trading Commission (CFTC) say that Sarao’s algorithm hammered the S&P E-Minis market for over two hours, putting roughly $200 million of negative pressure on the contract prices.

These high-frequency jolts allegedly created the conditions for the sudden plunge in equities prices in a market already sensitive due to European debt fears. The massive gyrations rocked the financial world and brought a wave of regulatory scrutiny to the practice of high-frequency trading, which received popular blame for the shock.

The FBI arrested Sarao Tuesday at his residence in the U.K., with cooperation from Scotland Yard and British financial regulators, according to the CFTC.